---
title: Environment variables
---

Environment variables can be added to resources using the `env_vars` parameter or the `env_file` parameter pointing to a `yaml` file. Examples

```python dev_resources.py
dev_fastapi = FastApi(
    ...
    env_vars={
        "RUNTIME_ENV": "dev",
        # Get the OpenAI API key from the local environment
        "OPENAI_API_KEY": getenv("OPENAI_API_KEY"),
        # Database configuration
        "DB_HOST": dev_db.get_db_host(),
        "DB_PORT": dev_db.get_db_port(),
        "DB_USER": dev_db.get_db_user(),
        "DB_PASS": dev_db.get_db_password(),
        "DB_DATABASE": dev_db.get_db_database(),
        # Wait for database to be available before starting the application
        "WAIT_FOR_DB": ws_settings.dev_db_enabled,
        # Migrate database on startup using alembic
        # "MIGRATE_DB": ws_settings.prd_db_enabled,
    },
    ...
)
```

```python prd_resources.py
prd_fastapi = FastApi(
    ...
    env_vars={
        "RUNTIME_ENV": "prd",
        # Get the OpenAI API key from the local environment
        "OPENAI_API_KEY": getenv("OPENAI_API_KEY"),
        # Database configuration
        "DB_HOST": AwsReference(prd_db.get_db_endpoint),
        "DB_PORT": AwsReference(prd_db.get_db_port),
        "DB_USER": AwsReference(prd_db.get_master_username),
        "DB_PASS": AwsReference(prd_db.get_master_user_password),
        "DB_DATABASE": AwsReference(prd_db.get_db_name),
        # Wait for database to be available before starting the application
        "WAIT_FOR_DB": ws_settings.prd_db_enabled,
        # Migrate database on startup using alembic
        # "MIGRATE_DB": ws_settings.prd_db_enabled,
    },
    ...
)
```

The apps in your templates are already configured to read environment variables.
